A '''fracture''' is the separation of an object or material into two or more pieces under the action of stress (physics)|stress
. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displacement develops perpendicular to the surface of displacement, it is called a normal tensile crack or simply a crack; if a displacement develops tangentially to the surface of displacement, it is called a shear crack, slip band, or dislocation.
'''Fracture strength''' or '''breaking strength''' is the stress when a specimen fails or fractures.
The word ''fracture'' is often applied to bone
s of living creatures (that is, a bone fracture
), or to crystal
s or crystalline materials, such as gemstone
s or metal
. Sometimes, in crystalline materials, individual crystals fracture without the body actually separating into two or more pieces. Depending on...